Pneumatic pump



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April 21, 1942. G. s. KNOX PNEUMATIC PUMP Filed June 25, 1938 5 Sheaefzs-Shee'cI -2 G. S. KNOX PNEUMATIC PUMP Filed June 23, 1938 ,lai

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April 2a, 1942. G. s. Nox

PNEUMATIQ PUMP Filed June 25, 1938- 3 Sheets-Sheet 3 J9 i w H1, H f///f/// f/A/J g p w a m //\v////////////// y u ,7// A Patented Apr. 21, 1942 UNITED STATES PATENT OFFICE rNEUMA'rrc PUMP A Granville S. Knox, Los Angeles, Calif. Application June Z3, 1938, Serial No. 215,373

es claims. (cl. a-234) This invention relates to pressure actuated pumping installations designed to be used in pumpin wells such as oil wells. It may be considered as an improvement over the disclosure made in my pending application entitled Gas lift pump, Serial No. 49,942, illed November 15, 1935, patened October 11, 1938, No. 2,132,738.

In my prior application there is disclosed a pumping installation for wells wherein the liquid of the well to be pumped is admitted past a valve to an eductionpassage through is to be elevated to the surface. Gas under pressure is continuously supplied to the installation and is periodically discharged into the eduction passage near the bottom of the column of liqui that collects therein by means' of a gas valve. The gas which is released by the gas valve into the eduction passage is eiective to bodily lift the slug of liquid therethrough to the surface.A

In my prior application the construction shown is such that the gas valve is open when the ratio which the liquid of pressure created by the column of well liquid'- in the eductionpassage to the gas pressure reaches a. predetermined value or fraction less than unity. The gas valve, however, is closed by means of a spring fective when the pressure in the eduction passage drops upon the slug of liquid being discharged at the surface. Consequently, with the arrangement of the gas valve structure in my prior ap-- plication the gas valve closes only upon a full reduction of the pressure in the eduction pas-` sage, this being required in order to enable the spring to become eiective to close the valve.

It is an object oi the present invention to pro-` vide an improved pressure actuated pumping installation which will not require a full reduction of the absolute pressure in the eduction passage to bring about a closing of the gas valve. Instead, in the present construction the gas valve is not only opened by the ratio of pressures in the induction and gas passages reaching a certain predetermined value, but it is also closed by the ratio of the same pressures falling below a predetermined value. In this manner. the improved construction is susceptible of being used under a' not necessary in order to accomplish a closing which constantly urges theA valve into closed position and which becomes efof the gas valve. Instead, all that is required is sufficient reduction of pressure in the eduction passage so that its ratio-to the pressure in the gas passage falls below a. predetermined value.A

Consequently, if the eduction passage has back pressure therein it is easily compensated for by merely increasing the gas pressure that is supplied to the gas passage.

The closing of the gas valve largely aectsthe rapidity of cycles of the apparatus and thepotential volume of liquid elevated during any given period. Accordingly, the flexibility of the apparatus disclosed in my prior application as to frequency of operation, maximum volumes obtain'- able, depths to which the installation may be used successfully, and as to conditions of back pressure in the education `passage is somewhat limited. In the present construction these-condi tions may vary widely and the construction may, nevertheless, be caused to 'operate satisfactorily and efficiently under all of them.

By the improved construction without modication or alteration it is possible to use the sameconstruction in deep wells as well as shallow wells. It also facilitates control from the surface as to frequency of operation and volume elevated during each cycle of operation. In this way, the unit'may be readily adjusted by varying the gas pressure to secure more eiiicient operation. Where State or governmental authorities permit only a pro rated allowable production from a given well the unit may be easily and quickly adjusted for this allowable produc-v tion without requiring structural changes or in any way sacrincing the emciency of the unit.

. Another object oi the invention is to provide I a gas lift pumping unit wherein the well liquid is allowed to enter the eduction passage past a liquid valve and to be elevated upon the release` of gas pressure which is released by a gas valve wherein the gasvalve is of such design as to have a smaller area exposed to gas pressure in the gas passage which urges the gas valve to close than the area which is exposed to pressure in the eduction passage which urges the gas valve to open. In this manner, theuse of springs in connection with thel gas valve can be eliminated completely and the gas valve will be opened when the ratio of pressure on the opposite sides of the gas valve reach a predetermined value and closed when the ratio of the-same pressures falls below a predetermined value. By proper design of the *gas valve the values of the opening and closing ratios may be very close together, or if the valve embodies a different design, the values f,

.to close whenever the pressure in the gas passage falls which is occasioned either by the opening of the gas valve or the absence of any material pressure in the gas passage. By employing the improved liquid valve, a relatively large main valve and passageway may be employed by providing a small pilot valve. The small pilot valve is influenced by pressures in the gas passage and serves to control the large main valve. In this way a relatively small pressure responsive means can beemployed in conjunction with the pilot valve causing it to be iniiuenced by the pres- 'sures that are present or absent in the gas passage but at the same time a much larger or main valve controlling a relatively large passage may be opened to admit liquid from the well with a minimum of frictionloss.

Still another object of the invention is to provide an improved booster or auxiliary construction .operable by the ascension of a slug of liquid in the eduction passage to release gas from a major gas supply at a point above locations where the gas is required to pass through relatively restricted passages to the pumping installation.

This gas that is thus released behind the ascending slug of liquid assists in elevating it to the surface. In this way, transmission losses may be considerably reduced in that the length of the small gas supply conduit from the main reservoir of gas down to the pumping unit may be kept small. After the slug of liquid has been started in its upward direction through the eduction passage by the gas supplied to the pumping unit a greater volume of gas may be released directly from the main reservoir behind the ascending slug without incurring friction losses that would otherwise be present in causing all of the gas to be released through the small gas supply conduit that leads to the pumping unit. Increased production is made possible by the booster or auxiliary construction because the power normally consumed in forcing gas through the restricted passages leading to the gas valve is used to lift the ascending slug through the eduction passage at increased velocities.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure l is a vertical section through a well illustrating the upper portion of the gas lift pumping unit embodying the present invention;

Fig. 2 is a continuation of the bottom of Fig. l illustrating the central `portion of the gas lift pumping unit embodying the invention; A

Fig. 3 is a continuation of thebottom of Fig. 2 illustrating the bottom portion, it being underlstood that Figs. l, 2, and 3 are somewhat in the nature of schematic illustrations;

Fig. 4 is a vertical section illustrating a preconstruction which is schematically illustrated in Fig. 2;

Fig. 5 is a continuation of the lower portion of Fig. 4 illustrating the preferred mechanical embodiment of that portion of the construction illustrated schematically in Fig. 3;

Fig. 6 is a horizontal section taken upon the line 6--8 upon Fig. 4;

Fig. 7 is a horizontal section taken substan tially upon the line 1-1 upon Fig. 4;

Fig. 8 is a horizontal section taken substantially upon the line 8-8 upon Fig. 4;

Fig. 9 is a horizontal section taken substantially upon the line 9-9 upon Fig. 4;

Fig. 10 is a horizontal section taken substantially upon theline Ill-I0 upon Fig. 5;

Fig. 1l is a horizontal section taken substantially upon the line II-II upon Fig. 5;

Fig. 12 is a vertical section through a form of gas valve that may be employed where it is desired that the gas valve close on low pressure in the eduction passage and open on high pressure in the eduction passage, the gas valve being shown in closed position;

Fig. 13 is a view similar to Fig. l2 illustrating the valve in open position and Fig. 14 is avertical section through an alternative form of gas valve of such design that closes on relatively high eduction passage pressures and opens on a somewhat lower eduction passage pressure. This type of valve may be employed where it is desired that the opening and closing, ratio of pressures in the eduction passage to that in the gas passage shall be very nearly the same.

Referring to the accompanying drawings l wherein similar reference characters designate ferred mechanical embodiment of the gas lift pumping unit, particularly that portion of the similar parts throughout, and referring specifically to Figs. 1, 2 and 3 in connection with which the principles of the present construction and operation will be described, I0 designates a well casing extending from substantially the top of the producing zone of the well to the surface. From the bottom of the casing there extends downwardly a perforated liner II, this being perforated and suitably suspended from the casing in conformity with any conventional5 oil well practice. Within the casing there is disposed a string of tubing I2 carrying a suitable casing packer I3 which is seated on the interior of the casing I0 providing an obstruction or barrier between the upper and lower portion of the casing around the tubing.

The casing is designed to have gas under pressure supplied toits interior around the tubing I2. This maybe supplied from any suitable source, and while it preferably is in the nature of natural gas it may be compressed air or any other suitable gas that can be utilized as a means for elevating the well fluid or liquid.

The space between tubing I2 and casing l0 above the casing packer I3 constitutes a main gas passage or gas reservoir in which a comparatively large volume of gas may be maintained under pressure. an eduction passage through which the liquid pumped is elevated to the surface.

Supported within the tubing I2 from a point above packer I3 is a string of inside, or macaroni tubing, I4. This tubing is o f comparatively small diameter and leads downwardly to the gas valve of the pumping unit. The gas in the main gas passage or reservoir between tubing i2 and casing I0 finds egress to the macaroni tubing I4 through an inlet port, I5. The macaroni tubing I 4 leads downwardly to a chamber I6 and is The interior of tubing i2 constitutes l aaaduee 3 suitably guided or centered by means of ribs or the equivalent forming a pump guide I1. Chamber I6 houses a metallic bellows I8 suspended at its upper end from a spider |9. The spider I9 has a stem 20 extending downwardly therefrom 5 about which the bellows I8 is disposed and the lower end of the bellows is attached to a gas valve 2| designed to seat downwardly against a seat 22 at the botto'm of chamber I6.

As will be noted from an inspection of Fig. 2, l0

bellows I8 occupies or blanks off a substantial portion of the upper surface of the gas valve 2| leaving only that. portion of the upper surface of the gas valve which is not occupied by the bellows to be exposed to gas pressure in chamber I8 l5 which urges it to close. The pressure on the inside of the bellows I8 and stem 2|) may be substantially atmospheric pressure. The closing effort exerted on thegas valve is thus that pres-v sure in chamber I6 which is effective on the 20 upper surface of the gas valve unoccupied by the bellows. The area on the underside of the gas valve 2| which is exposed within seat 22 is subjected to whatever pressure there is in tubing I2 which forms the eduction passage. This pres- 25 sure is transmitted to the underside of the gas valve 2| through ports 23. The area exposed on the underside of the gas valve to eduction passage pressure which urges the valve to open is greater than that area left exposed by bellows |8 on the 30 upper side of the gas valve which is subjected the gas pressure in chamber I6.

On the top of the seat 22 there is a collector ring 2l, seeFig. 4, which permits gas pressure in chamber I6-to be transmitted therethrough to 35 one or more passages 25 .when the gas valve 2| is closed. These passages 25 lead to a hollow stem 26,'see Figs. 3 and 5, around which is disposed a metal bellows 21, the upper end of which is attached to the top of a hollow stem and the 40 bottom of which is attached to a plunger 28. The plunger 28 is urged into its uppermost position by means of a spring 29 seated on a shoulder on the plunger surrounding stern 30. The stem 30 carried by the plunger extends downwardly 7,

and is designed to engage and unseat or open an upwardly closing liquid valve 3|. The liquid valve 3| is urged into closing position by means of a spring 32. In Fig. 3, I have illustrated this liquid valve as being merely in the form of a 59 ball valve for the purposes of simplicity and while a ball valve-may be used, the preferred construction of liquid valve employed is that illustrated in Fig. 5 to be hereinafter more fully described. 18e-:5

, neath the liquid valve 3| there is a standing valve 5,-, 33 the seat of which is provided by the bottom of the structure suspended by the macaroni tubing I4. The seat vfor the standing valve seats (in a suitable seat 3l near the bottom of the tubing I2. The tubing I2 may also carry a perforated 60 strainer 35.

Above port I5, see Fig. 1, I, in some instances, install an auxiliary or booster valve construction. The use of this booster valve is optional but is preferred. To this end the macaroni tubing I4 5;,

is extended a short distance above port I5 and is provided with a valve seat36 normally closed by an upwardly closing valve 31 carrying valve guides 38 and having an upwardly projecting valve stem 39. A hollow float 40 carrying guide 7:)

ribs 4I is vertically movable within the tubing I2 between stem 39, as a lower limit, and an internal shoulder which provides the upper limit. The weight of this float is such that when resting 0n stem 39 it is incapable of opening valve 31 75 column of liquid and is subsequently allowed to' drop when the bottom of the column has passed the float, its dropping inertia or momentum is capable of opening valve 31 against the pressure supplied to its underside through port I5. ATIhis is due to the fact that at the time the slug of liquid which is elevated through the eduction passage formed by tubing |2 has gas pressure behind it which reduces the pressure differential on opposite sides of the valve 31;also there is inertia of the dropping float.

The operation of the construction as above schematically described is as follows:

Well liquid such as oil, enters through the perforations in the liner II and if the formation pressure is insuicient to elevate this liquid to a point above ports 23 the entire'construction is lowered until the hydrostatic level of the well liquid due to formation pressure is above these ports. The liquid enters through the strainer 35 and passes upwardly past standing valve 33. Gas presure is supplied continually at the surface to the casing II) and finds ingress to the macaroni 'l tubing I4 through port I5. Prior to the supplying of this gas pressure, the liquid valve 3| remains closed by means of spring 32 so that well liquid cannot be forced into the unitv to cause heading up or the formation of a column of liquid above ports 23 which would .be too high to velevate by the gas pressure proposed to be used.l

Gas valve 2| being closed, the initial gas pressure nds ingress to passage 25 through the collector ring around the gas valve and from this point passes downwardly to the interior of stem 26 and bellows 21. This gas pressure thus transmitted to bellows 21 is effective to force plunger 29 downwardly against the action of spring 29 and the liquid valve 3| is thus forced open against the action of spring 32. Well liquid may then enter past the liquid valve and ow into the bottcm of the barrel formed by the bottom of tubing I2 through ports I5. The formation pressure will cause this well liquid to collect in a column extending above ports 23. The exposed bottom sur- 4at the surface the underside of gas valve 2| is merely subjected to the pressure created by this column of liquid. On the other hand, if the'eduction passage is subjected to back pressure the underside of gas valve 2| is exposed to the pressure created by the liquid column and the back pressure. The area on the underside of g'as valve 2| which is exposed to this pressure being greater than the effective area on the upper side of the gas valve that is subjected to the gas pressure in chamber I6, it is manifest that thegas valve will open when the pressure in ports 23 is a frac'- tion of the gas pressure in chamber I6. Thus, when the height of the liquid column above ports 23 is such that the ratio of pressures effective on the opposite sides of the gas valve reaches a predetermined value, the gas valve opens to release gas pressure from chamber I6 through ports" 23 to the bottom of the column of liquid extending thereabove. The released gas pressure lifts wise released or reduced. Thus, by reducing the pressure in bellows 21 so that the pressures on the interior and on the exterior of that bellows approach being equal, springs 29 and 32 become effective to close the liquid valve 3| in order to prevent the entrance of additional well iiuid until the ascending slug oi' liquid in the eduction passage formed by tubing I2 has been exhausted at the surface and the gas valve 2I has again closed.

As the slug or column of liquid is elevated in the eduction passage it encounters the iioat 40 lifting the float from the stem 39. When the ascending slug has completely passed the float -so that the float is no longer supported thereby,

the float drops. At the time that the float drops there is,of course. gas pressure on the underside of the slug and on the upperside of the valve 31. In other words, there is no great dierential in pressures on the opposite sides of this valve. Consequently, valve 311s opened by the float and gas in the main reservoir between tubing I2 and casing I0 enters through port I5 and is discharged into the eduction passage past valve 31. In this way, the gas may quickly flow from the main reservoir to the eduction passage behind the ascending slug and assist in elevating it to the surface. Such of the gas as is admitted to the eduction passage in this manner does not have to ow through the string of small macaroni tubing and thus friction-losses are reduced. If desired, additional auxiliary or booster valve constructions may be incorporated in tubing I2 at various elevations.

When the slug of vliquid is-discharged at the surface the pressure in the eduction passagefalls either to substantially atmospheric pressure or to the back pressure that may be maintained in the eduction passage. When pressure is reduced in the eduction passage, gas attempts to rush from chamber I6 past the gas valve 2|. However, due

to the restriction of gas flow around the gas valve 2| the ratio of pressure in port 23 to that in the Vchamber I6 falls below the predetermined opening ratio with the result that the gas valve 2| is again closed. The closing action of the gas valve may be somewhat assisted by the closing of the auxiliary valve 31. This valve will, of course, close when the slug is ejected from the eduction passage due to the fact that the pressure on the underside of the valve 31 is considerably in excess of the pressure remaining in tubing I2. When valve 31 closes, the impulse created in the flowing gas upon the closing is directed downwardly through the macaroni tubing and assists in causing gas valve 2| to close. When the gas valve closes, pressure again builds up in passages 25 through which it is transmitted to the interior of bellows 21. This results in the opening of the liquid valve 3|, as previously described, and the installation is then in condition for the accumulation of another column of liquid above ports 23 and for a succeeding cycle of operation.

It will be noted that in the present construction that the gas valve 2| is not only opened when the ratio of pressure in ports 23 to the pressure in the macaroni tubing exceeds a predetermined value, but that the gas valve is also subsequently closed when this same ratio of pressures falls below a predetermined value. Consequently, the closing of the gas valve as well as the opening is determined by the ratios of these pressures. Inasmuch as the gas valve is closed by a pressure ratio as distinguished from a'full reduction of absolute pressure and a thereupon operative spring, the improved construction is highly flexible in operation. Thus, if back pres-l sure is maintained on tubing I2 such as by a pressure gas trap or gas separator at the surface, this back pressure in no way affects the operation of the installation. When such back pressure is present additional pressure must be preserved in casing III and in the macaroni tubing to counterbalance or ,offset it. However, as the opening and closing of the gas valves is determined by pressure ratios, the maintaining of back pressure in the eduction passage does not affect the operation or require any modification or alteration. It consequently follows that the improved construction may be satisfactorily operated at virtually any depth desired. No modification or alteration in the construction is necessary to convert it from shallow well use to deep well use.

Where, for any reason, the production of the well must be held back, such as by governmental order or control, this may be easily accomplished without, reducing the efficiency of the apparatus. Thus, by merely controlling the pressures maintained in the casing I0 and in tubing I2, the operation of the installation may be varied to give any desired frequency of operation and also any desired quantity of production. These pressures which aiIect the operation can, of course, be controlled at the surface.

In Figs. 4 to 14, inclusive, I have illustrated preferred mechanical embodiments of the invention wherein the tubing is illustrated at I2 as before, and the macaroni tubing is illustrated at I4 guided by ribs or guides I1 which may be formed on a suitable adapter 46. The spider, indicated at I9, is suspended from a ring 41 which may be clamped between the adapter 46 and the top of the barrel of the installation. The bellows I8 is connected to the spider I9 and to the gas valve, generally designated at 2|. This gas valve in the preferred construction seats on a valve seat 43 which is 'surrounded by a ring 24. The upper portion of the gas valve 2| is ribbed and a small clearance 49 between the bottom of the gas valve and the surrounding structure permits the passage of gas from the macaroni tubing I4 to the collector ring 24.

In the preferred embodiment of the construction, the passages 25, see Figs. 4 and 9, are formed by a series of vertically drilled holes arranged between the ports 23. These drilled holes serve to convey gas pressure from within chamber I3 above valve seat 48 to the hollow stem 26 and the interior of the metallic bellows 21. The metallic bellows 21 is attached to the top of plunger 23 which is urged upwardly by spring 29. 'Ihe stern 30 on the plunger is engageable with the stem 50 of a pilot valve 5I which is urged upwardly by the spring 32. The pilot valve seats within a main valve 52 which, in turn, is adapted to seat on a valve seat 53. The main valve 52 is surrounded by a housing 54 preferably arranged `on top oi' the cage 55 for the standing valve 33.

In the preferred form of construction, whenplunger '23 is moved downwardly it first unseats the pilot valve 5I. This quickly equalizes pressure on the opposite sides of the main va1ve-52. When the pressures on opposite sides of the main smaller stem at 63.

spaanse valves are edualized, the :main valve may move downwardly with the pilot valve. Thus, although the formation pressures effective on the underside of the liquid valve may be quite high, the

pressure within bellows 2l need not be excedingly great to open the liquid valve against the high valve on being opened, opens a relatively large ingress passage through which the well liquid may pass with minimum friction. When the pilot valve moves the main valve to closing position, the main valve,`on approaching its seat, has the formation pressure beneath it eective to assist in seating the main valve.

In Figs. l2 and 13 I have illustrated a modified form of gas valve wherein the chamber is indicated at I, the spider at I9, and the bellows for the gas valve indicated at i8. In this form of construction the body of the valve presents a bottom surface indicated at 6i! which is exposed to the pressure in the eduction passage. The body of the valve is slightly larger, as indicated at 6l, than the seat and above the enlarged portion it tapers upwardly, as indicated at 62, to a A shoulder 64 extends inwardly around the stem leaving a clearance 65. This form of.valve construction is designed to close on low eduction tubing pressure and to open on high eduction tubing pressure. Thus, when the valve is closed, all portions of the valve above the seat which are not covered or blanked oil:` by

closely approach the area S0, an eduction pas? sage pressure which approaches the magnitude of the gas pressure in chamber i6 is required to open the valve. When the valve is opened, as

issuing from chamber i6 is subjected toa pressure drop between the shoulder 64 and the reduced stern portion 63 of the valve. In eifect, therefore, the only portions of the valve that are subjected to the gas pressure in chamber I6 when the valve ls open is that area left exposed between shoulder 6 and bellows i8. This area is somewhat smaller than the total area exposed to gas pressure in the position shown in Fig. 12. Consequently, with this design of valve the valve will close only when the eduction passage pressure is comparatively low. This form of valve is I' illustrated to show a construction wherein the pressure ratio required to. open the valve is quite different from the pressure ratio required to close the valve.

In the construction shown in Fig. 14, the chamber is indicated at i6, the spider at I9, and the bellows i8. The gas valve 2l has its bottom surface 22 exposed to eduction passage pressure. The upper surface of the valve which is exposed to gas pressure in chamber i6 is merely that surface which is left exposed by bellows i8. As these two areas remain constant in their eiective ability to be influenced by their respective pressures, and the area exposed on the upper portion cf the valve is a denite fraction of the area exposed on the lower portion of the valve, this type of valve construction may be employed eduction passage, a liquid valve controlling in-t Where it is desired to have the valve close at nearly the same pressure ratio as that required to open it.

From the above-described construction it will be appreciated that an improved ,gas lift pumping installation is provided which is highly :dexible in that it may be used under a large variety of varying conditions without requiring change or alteration. The operation of the construction may be'varied considerably without loss of efiicency by merely varying -.pressure conditions imposed upon the construction from the surface.

It should be noted that when the gas Valve starts to open in the present construction that gas pressure in chamber I6 is transferred to the underside of the valve 'and assists in snapping the gas valve open and holding it open until the pressure ratio falls to the closing ratio. Conversely, when the gas valve starts to close, pressure builds up on top of the gas valve tending to force it into closed position and to hold it closed. Consequently, there is no tendency in the construction for the gas valve to utter.

While it would be possible, in someinstances, to omit the liquid valve entirely, omission of the liquid valve would create a danger of the construction heading up prior to operation being started. There would also be danger of heading up whenever operation was stopped. Furthermore, the construction would then operate more in the nature of an aerating intermittent gas lift rather than a construction wherein a slug is bodilylifted which is preferred..

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. A gas lift pumping unit for wells comprising means defining an entering passage for theentry of well uid,`means defining an eduction passage through which the fluid may be elevated to the surface, means defining a gas passage through which gas under pressure may be supplied to the eduction passage, a liquid valve controlling ingress through the-entering passage, and a gas valve controlling ow of gas from the gas passage to the eduction passage, said gas valve being responsive under varying pressure `conditions to the ratio of pressures in the gas and eduction passages reaching a predetermined value which does not change under variation of pressure conditions to open the gas passage to release gas. therefrom into the eduction passage and beingH responsive to the rati-,o of said pressures falling below a predetermined value to close.

2. A gas lift pumping unit for wells comprising gress through the entering passage, anda gas valve controlling flow of gas from the gas passage to the eduction passage, said gas valve being so arranged as to have a smaller area exposed to gas pressurein the gas passage which urges the gas valve to close than the area exposed to pressure in the eduction passage which urges the gas valve to open whereby, when, under varying pressure conditions, the ratio of pressures in the gas and eduction passages reaches a predetermined 'value the gas valve will open to release gas into the eduction passage and when the ratio of pressures in said passages falls below a predetermined value the gas valve will close.

3. A gas lift pumping unit tor wells comprising means defining an enteringpassage for the entry of well liquid, means deiining an eduction passage through which the liquid may be elevated to the surface, means dening a gas passage through which gas under pressure may be supplied to the eduction passage, liquid valve means controlling the ilow through theI entering passage to the eduction passage, and means responsive to vpressures in the eduction and gas passages for opening the gas passage to the eduction passage when the ratio of pressure in the eduction passage to the pressure in the gas passage exceeds a predetermined value under varying pressure conditions, and for closing the gas passage When the pressure ratio in the eduction and gas passages falls below a predetermined value, said. pressure ratio values remaining constant under variations o! pressure conditions,iand means for closing the liquid valve when the gas passage is opened to the eduction passage and opening the liquid valve when the -gas passage is closed against egress to the eduction passage.

4. A gas lift pumping unit for wells comprisin means dening an entering passage for the entry of well liquid, means defining an eduction passage through which the liquidl may be elevated to the surface, means dening a gas passage through which gas under pressure may be supplied to the eduction passage, liquid valve means controlling the ow through the entering passage to the eduction passage, and .means responsive to pressures in the eduction and gas passages for opening the gas passage to the eduction passage whenthe ratio of pressure in the eduction passage to the pressure in the gas passage exceeds a predetermined value under varying pressure conditions, and for closing the gas passage when the pressure ratio in the eduction and gas passages falls below a predetermined value, said pressure ratio values remaining constant under variations of pressure conditions, and means for opening the liquid valve after the gas passage has been closed against egress to the eduction passage, and closing the liquid valve after the gas passage has been opened to the eduction passage.

5. A gas lift pumping unit for wells comprising means defining an entering passage for the entry of Well liquid, means defining an eduction passage through which the liquid may be elevated to the surface, means defining a gas passage through which gas under pressure may be supplied to .the eduction passage, liquid valve means controlling the iiow through the entering passage to the eduction passage, and means responsive to pressures in the eduction and gas passages for opening the gas passage to the eduction pasagewhen the ratio of pressure in the eduction passage to l the pressure in the gas passage exceedsa predey termined value, and for closing the gas passage when the pressure ratio in theeduction and gas passages falls below a predetermined value, said pressure ratio values remaining constant under variations of pressure conditions, and means responsive to pressure in the gas passage for opening the liquid valve when the gas passage is closed against egress to the eduction passage, and closing the liquid valve when the gas passage is opened to the eduction passage.

6. A gas lift pumping unit for wells comprising means deilning an ingress passage for the entry of well iiuid, means defining an eduction passage through which iluid may be elevated to the surface, valve means for admitting liquid to the eduction passage, means defining a gas pas.

sage through which gas under pressure may be supplied to the eduction passage, a gas valve controlling communication between the gas passage and the eduction passage, said gas valve being exposed on one side to pressures in the eduction passage which urge it to open and being exposed on the other side to pressures in the gas passage which urge it to close, said gas valve being so constructed and arranged that a lower pressure in the eduction passage than that present in the gas passage is capable of opening said valve, and that the opening and closing of the valve under varying conditions is controlled by a predetermined ratio of pressure in the eduction passage to that in the gas passage, said ratio remaining constant regardless of pressure conditions.

7. A gas lift pumping unit for wells comprising means deilning an ingress passage for the entry of well fluid, means delining an eduction passage through which fluid may be elevated to the surface, means deilning a gas passage through which gas under pressure may be supplied to the eduction passage, a gas valve controlling communication between the gas passage and the eduction passage, said gas valve being exposed on one side to pressures in the eduction passage which urge it to open and being exposed on the other side to pressures in the gas passage which urge it to close, said gas valve beingso constructed and arranged that a lower pressure in the eduction passage than that present in the gas passage is capable of opening said valve, and that *the opening and closing of the valve under varying conditions is controlled by a predetermined ratio of pressure in the eduction passage tothat in the gas passage, said ratio remaining constant regardless of actual pressures in the eduction and gas passages, a liquid valve controlling ingress to the eduction passage, and means responsive to pressures in the gas passage for openingthe liquid valve when the pressure in the gas passage is above a predetermined magnitude and closing the liquid valve when .the pressure in the gas passage is below said predetermined magnitude.

8. A gas lift pumping unit for wells comprising means defining an ingress passage provided for the ingress of well uid, means defining an eduction passage in which fluid may be elevated to the surface, means defining a gas vpassage through which gas under pressure may be supplied to the eduction passage, gas valve means controlling ow from the gas passage to the eduction passage, said gas valve being lso constructed as to be urged to be opened by pres-- sures in the eduction passage and urged to close by pressures in the gas passage but being arranged to open under varying pressure conditions when the ratio of pressure in the eduction passage to that in the gas passage exceeds a Acertain value and to close when said yratio falls below said value which ratio value remains constant regardless of the variation f -pressure conditions, and means for closing the ingress passage against reverse ilow therethrough.

9. A gas lift pumping unit comprising means defining ingress, eduction, and gas passages, gas valve means controlling the iiow of gas from the gas passage to the eduction passage having surfaces exposed to pressums in the gas and eduction passages whereby the pressure in the gas passage urges the valve to close and the presaccuses sure in the eduction passage urges the valve to open, and means to renderl a portion of the gas valve area on the gas passage side thereof non-responsive to gas pressure on the gas passage side or to pressure in the eduction passage.

10. A gas lift pumping unit comprising means defining ingress, eduction, and gas passages, gas valve means controlling the iiow of gas from tne gas passage to the eduction passage having surfaces exposed to pressures in the gas and eduction passages whereby the pressure in the gas passage urges the valve to close and the pressure in the eduction passage urges the valve to open, means to render a portion of the gas valve area on the gas passage side thereof non-responsive to gas pressure on the gas passage side or to pressure in the eduction passage, and means for closing the ingress passage against reverse flow therethrough.

11. In a gas lift `pumping unit wherein there are eduction and gas passages, means for admitting gas to the eduction passage from the gas passage so as to lift a column of fluid therein, a liquid valve controlling entry to the eduction passage from the Wellcomprising a pilot valve and a main valve, the pilot valve being so arranged that upon being opened' it will allow pressures on.

opposite sides of the main valve to balance;

12. In a gas lift pumping unit wherein there is an eduction passage and a gas passage, means for admitting gas to the eduction passage from the gas passage so as to lift a column of -fluid therein, a liquid valve controlling entry to the eduction passage from the well comprising a main valve and a seat therefor, a pilot valve seating on the main valve, and means for seat ing and unseating the pilot valve.

. i3. In a gas lift pumping unit wherein there are eduction and gas passages, means for admitting gas to the eduction passage from the gas passage so as to lift a column of fluid therein,

16. In a gas lift pumping unit wherein there are eduction and gas passages and wherein a column of iiuid in the eduction passage is elevated by gas discharged into the eduction passage from the gas passage beneath the column, means for admitting gas from the gas passage to the eduction passage to assist in elevating the column comprising a valve for opening the gas passage to the eduction passage, float means arranged to be dropped against the valve to open the valve, said float means being incapable of opening the valve by its own weight against the gas pressure in the gas passage but being so arranged as to be limitedly lifted by the ascending column of liquid and to be dropped against the valve so as to open it when the column passes thereby.

17. In a gas lift pumping unit for wells wherein there is a gas passage and an eduction pas-v sage, valve means for admitting liquid to the eduction passage, means for admitting gas prespressure on opposite sides of the valve sufficiently a. liquid valve controlling entry to the eduction passage from the well comprising a pilot valve and a main valve, the pilot valve being so arranged that upon being opened it will allow pressures on opposite sides oi the main valve to balance, and means for opening and closing the pilot valve responsive to pressures in the gas passage.

14. In a gas lift pumping unit wherein there are eduction and gas passages and wherein a column of liquid in the eduction passage is elevated by gas discharged into the eduction passage from the gas passage beneath the column, means for admitting gas to the eduction passage to assist in elevating the column comprising a valve arranged to be urged into closed position by the gas pressure, and float means adapted to be lifted by the liquid column being elevated in the eduction passage and to be lowered to open said valve upon the liquid column passing thereby.

15. In a gas lift pumping unit wherein there are eduction and gas passages and wherein a column of liquid in the eduction passage is elevated by gas discharged into the eduction passage from the gas passage beneath the column, means for admitting gas from the gas passage to the eduction passage to assist in elevating the column comprising a valve opening the`gas passage to the eduction passage, said valve being urged into closed position by gas pressure in the gas pas# sage, and float means adapted vto be lifted by the A liquid column being elevated in the eduction passage, and to be lowered to open said valve upon the column passing thereby.

low a certain value, which ratio value does notV change under varying pressure conditions.

18. In -a gas lift pumping unit for wells, a liquid valve adapted to be held closed by formation pressure, and means for balancing formation pressure on opposite sides of the valve so that said liquid valve may. be opened.

19. In a gas lift pumping unit for wells, a liquid valve adapted to be held closed by formation pressure, and means for balancing formation so that said liquid valve may be opened by a force less than that which would be required to Aopen the valve against the formation'pressure.

20. In a gas lift pumping unit for wells, means providing a gas passage and an eduction pas--v sage, valve means for admitting liquid to the" eduction passage, and means for opening and closing the gas'passage to the eduction passage influenced in its operation under varying `pressure conditions by pressures in the gas and educ'- .y tion passages, said means being so arranged and 1' constructed that under varying pressures in the gas passage it will open when the ratio of pressures in the eduction and gas passages exceeds a predetermined value which remains constantl under varying pressures and that it will close when said ratio falls short of said predetermined value.

' 21. In a gas lift pumping unit for wells, means Vproviding a gas passage and an eduction passage, valve means for admitting liquid to the eduction passage, and means for opening and closing the gas passage to the eduction passage l influenced in its operation under varying pres- 'itt sure conditions by pressures in the gas and eduction passages, said means being so arranged and constructed that under varying pressures inthe eduction passage it will open when the ratio of pressures in the eduction and gas passages exceeds a predetermined value and thatfit will close when said ratio falls short of said predetermined value which predetermined value remains constant under variation of pressures in said passages.

22. In a gas lift pumping unit for wells, means providing a gas passage and an eduction passage, valve means for admitting liquid to the eduction passage, and means for opening and closing the gas passage to the eduction passage influenced in its operation under varying pressure conditions by pressures in the gas and educu tion passages, said means being so arranged and constructed that under varying pressures in the gas and eduction passages it will open when the ratio of pressures in the eduction and gas passages exceeds a predetermined value and that it will close when said ratio falls short of said predetermined value which predetermined value remains constant under varying pressures.

23. A gas lift pumping unit for wells comprising means defining an entering passage for the entry of well uid, means defining an eduction passage through which the uid may be elevated to the surface, means deiining a gas passage through which gas under pressure may be supplied to the eduction passage, a liquid valve controlling ingress to the entering passage and a gas Valve controlling flow of gas from the gas passage to the eduction passage, said gas valve being responsive to the pressures in the gas and eduction passages whereby the valve is caused to open the gas passage into the eduction passage when a first predetermined ratio exists between the pressures in the gas and eduction passages and to close the gas passage into the eduction passage when a second predetermined ratio exists between the pressures in said eduction and gas'passages.

24. A gas lift pumping unit comprising means dening ingress, eduction', and gas passages, gas valve means controlling the flow of the gas from the gas passage to the eduction passage having surfaces exposed to pressures in the gas and eduction passages whereby the pressure in the gas passage urges the valve to close and the pressure in the eduction passage urges the valve to open, and means to render a portion of the gas valve area non-responsive to pressure in order to create a predetermined ratio between the areas exposed to gas and eduction passage pressures respectively.

25. A gas lift pumping unit for wells, means providing a gaspassage and an eduction passage, Valve means for admitting liquid to the eduction passage, and valve means for opening and closing the gas passage to the eduction pas-A sage and responsive in its operation to varying pressure conditions in the gas and eduction passages, said va`lve means being so arranged and constructed so that under varying pressures in the gas passage it will open when the iirst predetermined ratio exists between the pressures in the gas and eduction passages and close when a second predetermined ratio exists between the pressures in the gas and eduction passages which ratios remain constant under varying pressure conditions.

26. A gas lift pumping unit for wells comprising means defining an entering passage for the entry of well iiuid, means defining an eduction passage through which the fluid may be elevated to the surface, means defining a gas passage through which gas under pressure may be supplied to the eduction passage, a liquid valve controlling ingress through the entering passage, and a gas valve controlling iiow of gas from the gas passage to the eduction passage, said gas valve being responsive to the pressures in the gas and eduction passages whereby the valve is caused to open and close the gas passage into the eduction passage when a predetermined unvarying ratio exists between the pressures in the gas and eduction passages.

" 27. A gas lift pumping unit for wells comprising means defining an entering passage for the entry of well fluid, means defining an eduction passage through which the fluid may be elevated to the surface, means deiining a gas passage through which gas under pressure may be sup- .l

plied to the eduction passage, a liquid valve controlling ingress through the entering passage, and a gas valve controlling iiow of lgas from the gas passage to the eduction passage, said gas valve being responsive to the pressures in the gas and eduction passages whereby the valve is caused to open the gas passage into the eduction passage when a first predetermined unvarying ratio exists between the pressures in the gas and eduction passages and to close the gas passage into the eduction passage when a second predetemined unvarying ratio exists between the pressures in the last said passages.

28. A gas lift pumping unit for wells comprising means dening an entering passage for the entry of well fluid, means defining an eduction passage through which the fluid may be elevated to the surface, means defining a gas passage through which gas under pressure may be supplied to the eduction passage, a liquid valve controlling ingress through they entering passage, and a gas valve responsive to pressures in the gas and eduction passages for controlling flow of gas from the gas passage to the eduction passage, said gas valve being so arranged as to have a smaller area exposed to gas pressure in the gas passage which urges the gas valve to close than the area exposed to pressure in the eduction passage which urges the gas valve to open whereby the valve is caused to open and close the gas passage into the eduction passage when a predetermined ratio exists between the pressures in the gas and eduction passages.

29. A gas lift pumping unit for wells comprising means defining an entering passage for the entry of well fluid, means dening an eduction passage through which the fluid may be elevated to the surface, means deiining a gas passage through which gas under pressure may be supplied to the eduction passage; a liquid valve controlling ingress through the entering passage, and a gas valve responsive to pressures in the gas and eduction passages for controlling flow of gas from the gas passage to the eduction passage, said gas valve being so arranged as to have a smaller area exposed to gas pressure in the gas passage which urges the gas valve to 'Y close than the area exposed to pressure in the" eduction passage which urges the gas valveto open whereby the valve is caused to open-the gas passage into the eduction passage when a rst predetermined ratio exists between the pressures in the gas and eduction passages and to close the gas passage into the eduction passage when a second pedetermined ratio exists between the pressures in the last said passages.

30. A gas lift pumping unit for wells comprising means defining an entering passage for the entry of well liquid, means defining an eduction passage through which the liquid may be elevated to the surface. means defining a gas passage thrcugh which gas under pressure may be supplied to the eduction passage, liquid valve means controlling the flow through the entering passage to the eduction passage, and means responsive to pressures in the eduction and gas passages for opening and closing the gas passage to the eduction passage when a predetermined unvarying ratio exists between the pressures in the gas and eduction passages, and means for closing the liquid valve opened to the eduction passage and opening the liquid valve when the gas passage is closed against egress to the eduction passage.

31. A gas lift pumping unit for wells comprising means defining an entering passage for the entry of well liquid, means defining an eduction passage through which the liquid may be elevated to the surface, means dening a gas passage through which gas supplied Yto the eduction means controlling the ow passage tothe eduction sponsive to pressures passage, liquid valve through the entering passage, and means rein the eduction and gas passages for opening the gas passage into the eduction passage when a rst predetermined unvarying ratio exists between the pressures in the gas and eduction passages and to close the gas passage into the eduction passage when a second predetermined unvarying ratio exists between the pressures in the last said means for closing the liquid valve when v passage is opened to the eduction passage and under pressure may be stantial portion of the uninuenced by pressures therein leaving a rela'- tively small area to closed against egress to the eduction passage.

32. A- gas lift pumping unit for wells comprising means dening tion passage, means for opening and closing the gas passage to the eduction passage, controlled in its operation, by pressures in the gas and eduction passages, said means being so arranged and constructed that the uid pressure tending to close said means is applied to a smaller effective area when said means is open and to a larger effective areav when said means is closed. 33. In a gas lift pumping unit for wells, means providing a gas passage and an eduction passage, and a valve for opening and closing the gas passage to the eduction passage controlled in its operation by pressures in the gas and eduction passages, bellows means forrendering a subvalve in the gas passage be influenced by pressures therein, andfmeans providng a restricted passage around the body of the va1ve`betweenV said area and the seating surface of the valve.

GRANVILLE S. KNOX.

opening the liquid valve when the gas passage is a gas passage and an educ\ 

